Method of preserving edible material



April 4, 1961 w. L. MORRISON 2,978,336

METHOD oF PRESERVING EDIBLE MATERIAL Filed June '25. 1957 1N VEN TOR.

By Ml www UnitedStates Faremo t "szisssf l Y t ME'rHop/or PREsERv'ING EDBLE'MATERIAL Willard Langdon Morrison, Lake Forest, Ill., assigner, by

mesne assignments, to LiqefreezeCompany, Inc., New York, N.Y.,a corporationof New York Filed 'June 25,1951 ser. No'. 667,931 "1 claim. f(c'l.9919'2) f '2,978,336` Patented Apr. 4,1961

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Water Vapor to migrate from the Vrelatively warm-'air 't'o` the much colder nitrogen and as av result asboiling of vthe liquid nitrogen continues, the chamberwill be lletl with an atmosphere `of nitrogen, which atmosphere of nitrogen expels the air and water vapor `previously in the t chamber.

' v perature.

of other objects eventhoughnot'edible against deterioration resulting from contact with the air.

This application'is"'a"itintior1`in`part of my C- pending` application Serial Noi '5.77,'583, iiledApril 11, 1955, now abandoned. t 1 proposeropcktheniaf rialfwhich I wish to preserve vthe accompanying drawings, wherein?- ina gas'tighVcntine'r. Then to inject into the mass of i material in the container, `vpreferably far removed from the open mouth thereof, a supply of a cold boiling liquid such for example as Vliq1iid`nitroge`n yat atmospheric lpressure and temperature far below zero `degrees F. The relatively `warm material will furnish the latent heat to boil the liqud'and 'the resultant gas vvwill expand and be permeated throughout the entire mass, thus expelling most if not all of the air. The container may then be sealed containing the material to be preserved and an atmosphere of gaseous nitrogen. Under some circumstances the container and contents may be warmed before sealing. Under other circumstances, the container and contents may be chilled after sealing but in each case the sealed container will contain little if any atmospheric air to promote any of the deterioration processes to` which such materials are subject.

Emulsions, dressings, shortenings, oleomargarine and the like which are at times in semi-solid or semi-duid condition may also be similarly treated by the injection of liquid nitrogen and when that occurs, the gas expanding from the liquid will permeate and inflate the mass.

One of the important advantages of my invention is that a minimum of machinery is required. All that is necessary is a supply Vof liquid nitrogen and a nozzle for discharging it into the mass of material. Another advantage is that the discharge of a relatively small amount of liquid nitrogen and subsequent evaporation and expansion can take place very rapidly without long delays necessary when air or gas is to be churned into a thick viscous material.

Other objects will appear from time to timethroughout the specification and claim( The amount of liquid nitrogen injected into the vessel depends, of course, on the size of the vessel and the type of material stored therein and the temperature at which it is desired to seal the can. phase evolved as the liquid boils will be at the temperature of `-320 F. Since there wasl no water inthe liquid nitrogen, there will be no water in the nitrogen in gaseous phase as it boils oi from the liquid. The gaseous phase nitrogen being much colder and heavier than the air will tend as it expands to ll the chamber and expel the air with any water vapor in vaporous form in suspension therein. Since the gaseous nitrogen will be much colder than the air, there will be no tendency for any The nitrogen in gaseous' When the air and water vapor itherein have been expelled from the chamber and when all theliquid nitrogen has rboiled to gas., sealing of the chamber will prevent subsequent entry of air and water vapor. This sealing may takev placewhilefthe temperature of the chamber and contents, having been cooled by the introduction of the cold liquid nitrogen are still below the ambient tem- Under some circumstances, subsequent rise in temperature of a can, the contents of which was filled with cold nitrogen might be undesirable. Where that `is the case, the container might be warmed before seal` ing. Usually this will not be necessary Ybut such warming before sealing should always be sotcontrolled that no air or water vapor'will be drawn in-to the chamber. If after the can is sealed, cooling` results in a vacuum or reduced pressure, this will do no harm if the'seal iS adequate to prevent entrance of'airinto` the can until it is open for use.`

, I have .illustrated my invention vdiagrarnmatically in Figure 1 is a diagrammatic view in lparftj section;

t Figure 2 is allow diagram. v t i `Like parts are indicated-by like characters throughout the specification and drawings.

1 indicates an open mouth receptacle, the vmouth being located at the Vtop thereof. 3 is aremovable closue, 4 a ytube which may be thrust into the contents of the yesselthrough the o'pen mouth. 5 is a hose connecting the tube to a surceofiliqid nitrogen. '6 and 7 Vindicate valve which controls the ow of nitrogen into the receptacle. The cans, such as the can 1 of Figure l, are loaded at station 8. They are then conveyed by hand or machinery as the case may be to liquid nitrogen injection station 9, where the nitrogen is inserted, allowed to evaporate and expand to expel the air with resultant cooling of the contents of the'can. If desired, the can may then be conveyed to the can warming station 10 where the can is warmed by any suitable means. The water bath, the warm air blast, exposure to ambient air or any other warming is appropriate. Then the warmed can with the temperature of the contents thereof warmed, for example, up to the intended maximum to which it will be exposed, is taken to the can sealing station 11. There the can is sealed while still warm. Thence the cansl are taken to station 12 for storage, shipment or use.

'On the other hand, if it is not desired to raise the temperature of the can, the can after the nitrogen has been injected into it will bypass the warming station and go directly to the can sealing station where the can will be sealed at substantially the temperature resulting from the injection ofthe nitrogen.

If the can or vessel contains a granular powdered material, the tube which may take the form of something like a hypodermic needle may be thrust into the contents ot the vessel with the discharge adjacent the bottom thereof and the necessary amount of liquid nitrogen Will be injected. Granular materials even tho-ugh they may contain some moisture will under situations such as this not freeze together though the individual granules may be frozen. Thus, as the liquid nitrogen expands, the gas which is colder and heavier than the air will force the air upward as the level of the nitrogen gas rises until any gaseous content of the vessel other than the cold nitrogen will have been expelled. t

Under some circumstances all that is then necessary is to seal the vessel. However, itis sometimes desirable after the nitrogen has expanded from liquid to gaseous form and expelled the air from the vessel to raise the temperature of the vessel and its content to a point slightly above the maximum temperature to whichris expected the cold sealed vessel will be exposed. When this is done, the vessel under ordinary conditions ofsrhipment and storage will be at temperature below the maximum expected temperature and as arresult there will be no pressure in the vessel tending to burst it or cause leakage. A

As above indicated, while this invention is especially applicable tothe preserving of foodstuffs, it may equally well be appliedrto such objects as metal parts which, if

stored inAan atmosphere of nitrogen rather than air, will i be protected against corrosion, rusting and the like, this without reference to'A thesizeY of theobject or the size of the receptacle. Assuming, for example,Y that a valuable piece of machinery is enclosedvin a gastight chamber and a quantity of liquidnitrogen is deposited in the chamber, sufficient as it evaporates to expel the air and the water vapor, the machinery will then be in an atmosphere of nitrogen which is inert and the chamber may then be closed toV maintain such inert nitrogen atmosphere.

If only a few pieces of material are in the chamber, there will be little if any resistance to the expulsion of the air. If, however, the chamber contains granulated coffee for example, there ,will be substantial areas or voids between the grains which will at rst be filled with air and some time may be required before the expanding nitrogen can permeate through all these areas and expel a-ll the air. Therefore, the exact amount of nitrogen required depends on the sizes of the vessel and the character of the voids about the solids contained within the vessel. In every case only suicient liquid nitrogen needs to be applied to insure that when the nitrogen is all evaporated, the chamber is lled with the nitrogen atmosphere, or if it is desired substantially to lower the temperature, the amount of liquid nitrogen will be increased or the can may be subjected to external cooling methods.

Such external cooling must of course take place after the supply of nitrogen has ceased and the can is cooled because otherwise cooling the contents unsealed, with nitrogen no longer being supplied, could result in return of ambient air to the contents ofthe can.

I claim:

The method of treating edible material which consists in first packaging the material in an openrtop uid-tight container exposed to ambient atmosphere, then discharging into the container adjacent the bottom ofthe mass of material contained therein -in direct and intimate contact with such material at approximately atmospheric pressure and at a temperature far below ,the temperature of the container contents and ambient air a supply of liquid nitrogen and continuing such supply until the contents of the container have supplied sufficient latent heat to boil and expand the liquid to gaseous phase and the resultant gas has filled the containerA and expelled the air therefrom, raising the temperature of the container and contents to approximately ,the temperature of the ambient air and thereafter sealing the container. i

References Cited in the ile of this patent UNITED STATES PATENTS 2,131,181 KantorY Sept. 27, 1938 2,159,835 Waters May 23, 1939 2,541,441 Sharp et al. Feb. 13, 1951 2,569,217 Bagdigian Sept. 25, 1951 2,583,697 Hendry et al Jan. 29, 1952 FOREIGN PATENTS 521,715 Great Britain May 29, 1940 OTHER REFERENCES yFood Industries, September 1949, pp. 37, 38, and 192.` 

